Hpyerglycemic and anti-diabetic nephritis activities of polysaccharides separated from Auricularia auricular in diet-streptozotocin-induced diabetic rats

Due to substantial morbidity and complications including nephropathy, a search for alternative treatment of diabetes mellitus is urgently required. The present study aimed to investigate the hypoglycemic and anti-diabetic nephropathy activities of polysaccharides separated from Auricularia auricular (AAP). Diet streptozotocin (STZ)-induced diabetic Sprague-Dawley rats were orally treated with metformin (100 mg/kg; positive control) and AAP (100 and 400 mg/kg) for four weeks, and parameters in the serum and liver associated with blood glucose, free radicals and nephropathy were determined. Similar to metformin, AAP treatment strongly reduced blood glucose levels by promoting glucose metabolism. The anti-oxidative activity of AAP, which was indicated by the modulation of superoxide dismutase, glutathione peroxidase, reactive oxygen species and methane dicarboxylic aldehyde levels in serum, was observed in diabetic rats. Furthermore, the regulatory effects of AAP on blood urea nitrogen, creatinine, uric protein and inflammatory-related factors revealed its protection against diabetic nephropathy. The present data suggests that AAP-mediated anti-diabetic and anti-nephritic effects are partially associated with their modulations on the anti-oxidative system and nuclear factor kappa B-related signaling pathway. In conclusion, AAP has potential to be a novel source of treatments for diabetes.